#include <bits/stdc++.h>
using namespace std;
#define fast_io ios::sync_with_stdio(false); cin.tie(nullptr);
#pragma GCC optimize("Ofast,no-stack-protector,unroll-loops,fast-math")
typedef long long ll;
typedef long double ld;
#define chmin(a,b) a = min(a,b);
#define chmax(a,b) a = max(a,b);
#define bit_count(x) __builtin_popcountll(x)
#define leading_zero_count(x) __builtin_clz(x)
#define trailing_zero_count(x) __builtin_ctz(x)
#define gcd(a,b) __gcd(a,b)
#define lcm(a,b) a / gcd(a,b) * b
#define rep(i,n) for(int i = 0 ; i < n ; i++)
#define rrep(i,a,b) for(int i = a ; i < b ; i++)
#define repi(it,S) for(auto it = S.begin() ; it != S.end() ; it++)
#define pt(a) cout << a << endl;
#define debug(a) cout << #a << " " << a << endl;
#define all(a) a.begin(), a.end()
#define endl "\n";
#define v1(n,a) vector<ll>(n,a)
#define v2(n,m,a) vector<vector<ll>>(n,v1(m,a))
#define v3(n,m,k,a) vector<vector<vector<ll>>>(n,v2(m,k,a))
#define v4(n,m,k,l,a) vector<vector<vector<vector<ll>>>>(n,v3(m,k,l,a))
template<typename T,typename U>istream &operator>>(istream&is,pair<T,U>&p){is>>p.first>>p.second;return is;}
template<typename T,typename U>ostream &operator<<(ostream&os,const pair<T,U>&p){os<<p.first<<" "<<p.second;return os;}
template<typename T>istream &operator>>(istream&is,vector<T>&v){for(T &in:v){is>>in;}return is;}
template<typename T>ostream &operator<<(ostream&os,const vector<T>&v){for(auto it=v.begin();it!=v.end();){os<<*it<<((++it)!=v.end()?" ":"");}return os;}
template<typename T>istream &operator>>(istream&is,vector<vector<T>>&v){for(T &in:v){is>>in;}return is;}
template<typename T>ostream &operator<<(ostream&os,const vector<vector<T>>&v){for(auto it=v.begin();it!=v.end();){os<<*it<<((++it)!=v.end()?"\n":"");}return os;}
template<typename T>ostream &operator<<(ostream&os,const set<T>&v){for(auto it=v.begin();it!=v.end();){os<<*it<<((++it)!=v.end()?" ":"");}return os;}
template<typename T>ostream &operator<<(ostream&os,const multiset<T>&v){for(auto it=v.begin();it!=v.end();){os<<*it<<((++it)!=v.end()?" ":"");}return os;}

const int mod = 998244353 ;

template< int mod >
struct ModInt {
    int x;

    ModInt() : x(0) {}

    ModInt(int64_t y) : x(y >= 0 ? y % mod : (mod - (-y) % mod) % mod) {}

    ModInt &operator+=(const ModInt &p) {
        if((x += p.x) >= mod) x -= mod;
        return *this;
    }

    ModInt &operator-=(const ModInt &p) {
        if((x += mod - p.x) >= mod) x -= mod;
        return *this;
    }

    ModInt &operator*=(const ModInt &p) {
        x = (int) (1LL * x * p.x % mod);
        return *this;
    }

    ModInt &operator/=(const ModInt &p) {
        *this *= p.inverse();
        return *this;
    }

    ModInt operator-() const { return ModInt(-x); }

    ModInt operator+(const ModInt &p) const { return ModInt(*this) += p; }

    ModInt operator-(const ModInt &p) const { return ModInt(*this) -= p; }

    ModInt operator*(const ModInt &p) const { return ModInt(*this) *= p; }

    ModInt operator/(const ModInt &p) const { return ModInt(*this) /= p; }

    bool operator==(const ModInt &p) const { return x == p.x; }

    bool operator!=(const ModInt &p) const { return x != p.x; }

    ModInt inverse() const {
        int a = x, b = mod, u = 1, v = 0, t;
        while(b > 0) {
            t = a / b;
            swap(a -= t * b, b);
            swap(u -= t * v, v);
        }
        return ModInt(u);
    }

    ModInt pow(int64_t n) const {
        ModInt ret(1), mul(x);
        while(n > 0) {
            if(n & 1) ret *= mul;
            mul *= mul;
            n >>= 1;
        }
        return ret;
    }

    friend ostream &operator<<(ostream &os, const ModInt &p) {
        return os << p.x;
    }

    friend istream &operator>>(istream &is, ModInt &a) {
        int64_t t;
        is >> t;
        a = ModInt< mod >(t);
        return (is);
    }

    static int get_mod() { return mod; }
};

using modint = ModInt< mod >;

const int MAX_N = 2010101 ;

modint inv[MAX_N+1] ; // (n!)^(p-2) (mod p) を格納
modint fac[MAX_N+1] ; // (n!) (mod p) を格納

modint powmod(modint x , ll n){
    modint res = 1 ;
    while(n > 0){
        if(n & 1) res *= x;
        x *= x;
        n >>= 1 ;
    }
    return res ;
}

// 階乗の逆元(n!)^(-1)のmodを配列に格納
void f(){
    inv[0] = 1 ; inv[1] = 1 ;
    for(ll i = 2 ; i <= MAX_N ; i++){
        inv[i] = powmod(i,mod-2) * inv[i-1];
    }
}

// 階乗のmodを配列に格納
void g(){
    fac[0] = 1 ; fac[1] = 1 ;
    for(ll i = 2 ; i <= MAX_N ; i++){
        fac[i] = fac[i-1] * i;
    }
}

//nCrの計算
modint combination(ll n , ll r){
    if(n < 0 || r < 0 || n < r) return 0 ;
    return fac[n] * inv[n-r] * inv[r];
}

modint permutation(ll n , ll r){
    if(n < 0 || r < 0 || n < r) return 0 ;
    return fac[n] * inv[n-r];
}

void init(){ f() ; g() ; }

void solve(){
    init();
    ll n, k;
    cin >> n >> k;
    ll tot = 2 * n + 4;
    ll sym = (n - 2) / 2;
    if(n & 1){
        if(k % 2 == 0){
            ll h = k / 2;
            modint sum = 0;
            modint dup = 0;
            dup += combination(sym,h);
            dup += combination(sym,h-1);
            dup *= 2;
            sum += combination(tot,k);
            sum -= dup;
            sum /= 4;
            sum += dup;
            pt(sum);
        }
        else{
            ll h = (k - 1) / 2;
            modint sum = 0;
            modint dup = 0;
            dup += combination(sym,h);
            dup *= 2;
            sum += combination(tot,k);
            sum -= dup;
            sum /= 4;
            sum += dup;
            pt(sum);
        }
    }
    else{
        if(k % 2 == 0){
            ll h = k / 2;
            modint sum = 0;
            modint dup = 0;
            dup += combination(sym,h);
            dup *= 2;
            sum += combination(tot,k);
            sum -= dup;
            sum /= 4;
            sum += dup;
            pt(sum);
        }
        else{
            modint sum = 0;
            sum += combination(tot,k);
            sum /= 4;
            pt(sum);
        }
    }
}

int main(){
    fast_io
    int t = 1;
    // cin >> t;
    rep(i,t) solve();
}